Radio frequency identification (RFID) systems operating in the high-frequency range, typically at 13.56 Megahertz (MHz), are radiation limited by governmental regulations, such as the Federal Communications Commission (FCC) rules governing the industrial, scientific, and medical (ISM) operating bands commonly used for these unlicensed systems, in particular 47CFR15.225. These RFID systems are commonly known as vicinity readers because they are capable of reading credit card sized RFID cards to a distance of 60 centimeters (about two feet).
Conventional RFID systems are vulnerable to eavesdropping from unauthorized devices which may intercept and receive information in the RF domain. Such information may include transactional information, such as passwords transmitted during RFID card authentication transactions and/or personal data. In response to efforts to expand the use of RFID enabled documents and devices, organizations advocating greater public privacy and security protections have raised concerns over RFID system vulnerabilities. These concerns have limited industry efforts to make RFID systems more widely available for a variety of useful applications.